Biomaterial Database

Kinetic mechanism of NADH-dependent glutamate synthase from lupin nodules. 1979

M J Boland

From initial-rate studies, a partially random kinetic mechanism has been deduced for NADH-dependent glutamate synthase from lupin nodules. The mechanism involves compulsory binding of NADH as first substrate, followed by random-order binding of glutamine and 2-oxoglutarate. Patterns of inhibition by glutamate substantiate the mechanism. Dithionite was incapable of acting as an alternative reducing substrate although it is known to reduce the flavine groups of the enzyme. The implications of these results are discussed. Published rate equations for this type of mechanism were found to be unsatisfactory for this enzyme and suitable new equations are produced. These equations should have general application where the obligatory first substrate binds very tightly.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009243	NAD	A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)	Coenzyme I,DPN,Diphosphopyridine Nucleotide,Nadide,Nicotinamide-Adenine Dinucleotide,Dihydronicotinamide Adenine Dinucleotide,NADH,Adenine Dinucleotide, Dihydronicotinamide,Dinucleotide, Dihydronicotinamide Adenine,Dinucleotide, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide,Nucleotide, Diphosphopyridine
D010944	Plants	Multicellular, eukaryotic life forms of kingdom Plantae. Plants acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations. It is a non-taxonomical term most often referring to LAND PLANTS. In broad sense it includes RHODOPHYTA and GLAUCOPHYTA along with VIRIDIPLANTAE.	Plant
D004227	Dithionite	Dithionite. The dithionous acid ion and its salts.	Hyposulfite,Sodium Dithionite,Dithionite, Sodium
D005970	Glutamate Synthase	An enzyme that catalyzes the formation of 2 molecules of glutamate from glutamine plus alpha-ketoglutarate in the presence of NADPH. EC 1.4.1.13.	Glutamine Ketoglutarate Amidotransferase,Ketoglutarate Glutamine Amidotransferase,Amidotransferase, Glutamine Ketoglutarate,Amidotransferase, Ketoglutarate Glutamine,Glutamine Amidotransferase, Ketoglutarate,Ketoglutarate Amidotransferase, Glutamine,Synthase, Glutamate
D000637	Transaminases	A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. (Dorland, 28th ed) EC 2.6.1.	Aminotransferase,Aminotransferases,Transaminase